Re: libata-acpi: allow _GTF on SATA, but disable on PATA for now

[Jeff Garzik <jeff@garzik.org>]

Linux Kernel Mailing List wrote:
> Gitweb:     http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=df33c77e3981e71afc8727ee5c432ba1a1bba68c
> Commit:     df33c77e3981e71afc8727ee5c432ba1a1bba68c
> Parent:     908e0a8a265fe8057604a9a30aec3f0be7bb5ebb
> Author:     Kristen Accardi <kristen.c.accardi@intel.com>
> AuthorDate: Fri Mar 9 18:15:33 2007 -0500
> Committer:  Len Brown <len.brown@intel.com>
> CommitDate: Fri Mar 9 18:15:33 2007 -0500
> 
>     libata-acpi: allow _GTF on SATA, but disable on PATA for now
>     
>     The ACPI specification states, and BIOS implementations depend on,
>     _STM being called before _GTF.
>     
>     SATA does this, but PATA does not.  So for now, simply
>     prevent execution of _GTF on PATA devices.  Longer term we
>     should implement ACPI support for PATA devices in libata.
>     
>     Signed-off-by: Kristen Accardi <kristen.c.accardi@intel.com>
>     Signed-off-by: Len Brown <len.brown@intel.com>
> ---
>  drivers/ata/libata-acpi.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
> index d14a48e..89aaf74 100644
> --- a/drivers/ata/libata-acpi.c
> +++ b/drivers/ata/libata-acpi.c
> @@ -561,6 +561,13 @@ int ata_acpi_exec_tfs(struct ata_port *ap)
>  
>  	if (noacpi)
>  		return 0;
> +	/*
> +	 * TBD - implement PATA support.  For now,
> +	 * we should not run GTF on PATA devices since some
> +	 * PATA require execution of GTM/STM before GTF.
> +	 */
> +	if (!(ap->cbl == ATA_CBL_SATA))
> +		return 0;
>  
>  	for (ix = 0; ix < ATA_MAX_DEVICES; ix++) {
>  		if (!ata_dev_enabled(&ap->device[ix]))

Grumble!

This /really/ should have gone through me and linux-ide first.

Alan has been actively working on PATA ACPI, and we have been debugging 
ACPI issues as well.  PLEASE coordinate with the maintainer, when 
touching code outside of drivers/acpi!

AFAICS this patch went in with zero appearance on LKML or another 
related list, until submission.  This is /not/ how we do Linux development.

	Jeff